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Su C, Wang F. Clinical and molecular findings in a family expressing a novel heterozygous variant of the G elongation factor mitochondrial 1 gene. Exp Ther Med 2020; 20:173. [PMID: 33093908 PMCID: PMC7571333 DOI: 10.3892/etm.2020.9303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/29/2020] [Indexed: 12/14/2022] Open
Abstract
The identified mutations in the G elongation factor mitochondrial 1 (GFM1) gene have been associated with heterogeneous clinical features of an early-onset mitochondrial disease in only 25 families. The present study reports the case of two siblings with a novel GFM1 variant and their clinical and laboratory presentations, which included progressive hepatic encephalopathy, failure to thrive and persistent lactic acidemia. Both histological changes and diminished expression of the GFM1 protein were observed in the liver and kidney tissues of the index patient. Whole-exome and Sanger sequencing technologies were used to diagnose the index patient with defective GFM1 using amniocentesis at 32 weeks' gestation. Heterozygous mutations in the GFM1 gene were identified in both siblings: A novel mutation, C1576T in exon 13 inherited from their asymptomatic mother, resulting in a premature stop codon at amino acid position 526 and the previously reported G688A mutation on the boundary between exon 5 and intron 5-6, inherited from their asymptomatic father. In conclusion, the present study reports two siblings carrying a novel GFM1 variant with a rare fatal mitochondrial disease.
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Affiliation(s)
- Chang Su
- Department of Obstetrics and Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, P.R. China
| | - Fangfang Wang
- Department of Obstetrics and Gynecology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310006, P.R. China
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Glasgow RIC, Thompson K, Barbosa IA, He L, Alston CL, Deshpande C, Simpson MA, Morris AAM, Neu A, Löbel U, Hall J, Prokisch H, Haack TB, Hempel M, McFarland R, Taylor RW. Novel GFM2 variants associated with early-onset neurological presentations of mitochondrial disease and impaired expression of OXPHOS subunits. Neurogenetics 2017; 18:227-235. [PMID: 29075935 PMCID: PMC5705740 DOI: 10.1007/s10048-017-0526-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 10/03/2017] [Indexed: 11/29/2022]
Abstract
Mitochondrial diseases are characterised by clinical, molecular and functional heterogeneity, reflecting their bi-genomic control. The nuclear gene GFM2 encodes mtEFG2, a protein with an essential role during the termination stage of mitochondrial translation. We present here two unrelated patients harbouring different and previously unreported compound heterozygous (c.569G>A, p.(Arg190Gln); c.636delA, p.(Glu213Argfs*3)) and homozygous (c.275A>C, p.(Tyr92Ser)) recessive variants in GFM2 identified by whole exome sequencing (WES) together with histochemical and biochemical findings to support the diagnoses of pathological GFM2 variants in each case. Both patients presented similarly in early childhood with global developmental delay, raised CSF lactate and abnormalities on cranial MRI. Sanger sequencing of familial samples confirmed the segregation of bi-allelic GFM2 variants with disease, while investigations into steady-state mitochondrial protein levels revealed respiratory chain subunit defects and loss of mtEFG2 protein in muscle. These data demonstrate the effects of defective mtEFG2 function, caused by previously unreported variants, confirming pathogenicity and expanding the clinical phenotypes associated with GFM2 variants.
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Affiliation(s)
- Ruth I C Glasgow
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Kyle Thompson
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Inês A Barbosa
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, UK
| | - Langping He
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Charlotte L Alston
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Charu Deshpande
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, UK
| | - Michael A Simpson
- Department of Medical and Molecular Genetics, King's College London School of Medicine, London, UK
| | - Andrew A M Morris
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
- Alder Hey Children's Hospital NHS Foundation Trust, Liverpool, UK
| | - Axel Neu
- University Children's Hospital, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ulrike Löbel
- Department of Diagnostic and Interventional Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Julie Hall
- Department of Neuroradiology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
| | - Holger Prokisch
- Institute of Human Genetics, Helmholtz Zentrum München, Oberschleißheim, Germany
- Institute of Human Genetics, Technische Universität München, Munich, Germany
| | - Tobias B Haack
- Institute of Human Genetics, Technische Universität München, Munich, Germany
- Institute of Medical Genetics and Applied Genomics, University of Tübingen, Tübingen, Germany
| | - Maja Hempel
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Robert McFarland
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Newcastle upon Tyne, NE2 4HH, UK.
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